and soon becomes a pressing sensation that's impossible to ignore.

然後漸漸一股迫切感覺，讓人無法忽視

Finally, it's all you can think about, and out of sheer desperation, you go on a hunt for a bathroom until "ahh."

最後，你可想而知，不顧一切你直接衝往廁所，直到「解放」

Humans should urinate at least four to six times a day,

人類一天應該要小便至少四到六次

but occasionally, the pressures of modern life forces us to clench and hold it in.

但是偶然地，現代生活的壓力強迫我們收緊和撐著這個念頭

How bad is this habit, and how long can our bodies withstand it?

這個習慣有多糟？我們身體禁得起忍耐多久？

The answers lie in the workings of the bladder,

答案就在膀胱的工作方式

and oval pouch that sits inside the pelvis.

它位於骨盆內的橢圓形袋子

Surrounding this structure are several other organs

圍繞在膀胱附近的數個器官

that together make up the whole urinary system.

它們一起形成整個的泌尿系統

Two kidneys,

二顆腎臟

two ureters,

二條輸尿管

two urethral sphincters,

二塊尿道的括約肌

and a urethra.

還有一個尿道

Constantly trickling down from the kidneys is the yellowish liquid known as urine.

不斷地從腎臟滴下來黃色液體是尿液

The kidneys make urine from a mix of water and the body's waste products,

腎臟的功能是混合水和身體產生的廢棄物製造尿液

funneling the unwanted fluid into two muscular tubes called ureters.

如漏斗般將無用的液體導入二根肌肉管狀器官稱為輸尿管

These carry it downward into the hollow organ known as the bladder.

將這些液體往下運到一個中空的器官就是膀胱

This organ's muscular wall is made of tissue called detrusor muscle

這個器官的肌肉壁由一層薄膜，稱為逼尿肌

which relaxes as the bladder fills allowing it to inflate like a balloon.

讓膀胱在滿的時候鬆弛，讓它膨脹像是一個氣球

As the bladder gets full, the detrusor contracts.

當膀胱有要滿了，逼尿肌開始收縮

The internal urethral sphincter automatically and involuntarily opens,

內部的尿道括約肌自動非自願地打開

and the urine is released.

然後排尿

Whooshing downwards, the fluid enters the urethra

尿液飛快的向下移動進入到尿道

and stops short at the external urethral sphincter.

停在外部的尿道的括約肌

This works like a tap.

這個作用像是一個水龍頭

When you want to delay urinating, you keep the sphincter closed.

當你想要晚點再上時，就讓括約肌保持關閉

When you want to release it, you can voluntarily open the flood gates.

當你想要小便時，你可以自願地再把水門打開

But how do you sense your bladder's fullness

但你如何感知你膀胱要滿的狀態

so you know when to pee?

使你知道何時去撒尿

Inside the layers of detrusor muscles are millions of stretch receptors

在逼尿肌的內層有數百萬延伸出的感覺器官

that get triggered as the bladder fills.

在膀胱滿的時候被觸發

They send signals along your nerves to the sacral region in your spinal cord.

它們發出信號沿著神經到位於脊椎神經的薦骨區域

A reflex signal travels back to your bladder,

一個反射信號送回到你的膀胱

making the detrusor muscle contract slightly,

讓逼尿肌輕微地收縮

and increasing the bladder's pressure so you're aware that it's filling up.

增加膀胱的壓力，所以你就察覺到膀胱要滿了

Simultaneously, the internal urethral sphincter opens.

同時地，內部的尿道的括約肌打開

This is called the micturition reflex.

這個稱為排尿反射

The brain can counter it if it's not a good time to urinate

在大腦可以反對它，如果這並非一個對的時間去小便

by sending another signal to contract the external urethral sphincter.

藉由送出另一個信號去收縮外部尿道的括約肌

With about 150 to 200 milliliters of urine inside of it,

當它裡面大約有 150 到 200 毫升左右的尿液

the bladder's muscular wall is stretched enough

膀胱的肌肉壁還足夠伸展

for you to sense that there's urine within.

讓你意識到裡面有尿

At about 400 to 500 milliliters, the pressure becomes uncomfortable.

達到大約 400 到 500 毫升，有一股壓力開始覺得不自在

The bladder can go on stretching, but only to a point.

膀胱還能夠伸展，但只剩一點空間

Above 1,000 milliliters, it may burst.

超過 1000 毫升，它會炸裂

Most people would lose bladder control before this happens,

大部份的人們都會控制在膀胱失控前，解除警報

but in very rare cases,

但有一些罕見例子

such as when a person can't sense the need to urinate,

像當一個人他無法感覺到尿意

the pouch can rupture painfully requiring surgery to fix.

會感到膀胱會痛苦地破裂，需要外科醫生修復它

But under normal circumstances,

但在一般情況下

your decision to urinate stops the brain's signal to the external urethral sphincter,

你下決定要小便就會停止大腦發送信號給外部括約肌

causing it to relax and the bladder to empty.

讓肌肉放鬆，排出膀胱的尿液

The external urethral sphincter is one of the muscles of the pelvic floor,

外部尿道的括約肌是骨盆底的其中一塊肌肉

and it provides support to the urethra and bladder neck.

它提供支撐在尿道和膀胱頸

It's lucky we have these pelvic floor muscles

很幸運我們擁有這些骨盆底肌肉

because placing pressure on the system by coughing,

因為當泌尿系統受到擠壓，發生咳嗽

sneezing,

打噴嚏

laughing,

大笑

or jumping could cause bladder leakage.

或跳躍都會造成膀胱洩漏

Instead, the pelvic floor muscles keep the region sealed

然而，骨盆底的肌肉封起這部位

until you're ready to go.

直到你打算小便

But holding it in for too long,

但若維持這個狀態太久、

forcing out your urine too fast,

排出的速度太快、

or urinating without proper physical support

或小便時沒有適合的物理支撐

may over time weaken or overwork that muscular sling.

可能會隨著時間虛弱或肌肉的懸帶工作過度

That can lead to an overactive pelvic floor,

導致骨盆底肌肉過度活躍

bladder pain,

膀胱疼痛

urgency,

緊急

or urinary incontinence.

或尿失禁

So in the interest of long-term health,

所以為了長遠健康的利益

it's not a great habit to hold your pee.

忍住不去小便不是一個好習慣

But in the short term, at least, your body and brain have got you covered,

但從短期來看，至少你的身體和大腦可以幫你應付一陣子

so you can conveniently choose your moment of sweet release.

讓你選擇一個方便甜美的時刻去解放